This project is designed to study mutagenesis using monospecific antibodies against the sperm specific enzyme, lactic dehydrogenase-X. The antiserum against mouse LDH-X has been characterized and its cross reaction with rat LDH-X has been studied. An immunofluorescent technique has been developed to label the mouse and rat sperm using the horse anti-LDH-X antibody and FITC-labeled goat anti-horse IgG antibody.